Context. Debris discs are a consequence of the planet formation process and constitute the fingerprints of planetesimal systems. Their solar system's counterparts are the asteroid and Edgeworth-Kuiper ... [more ▼]

Context. Debris discs are a consequence of the planet formation process and constitute the fingerprints of planetesimal systems. Their solar system's counterparts are the asteroid and Edgeworth-Kuiper belts. Aims. The DUNES survey aims at detecting extra-solar analogues to the Edgeworth-Kuiper belt around solar-type stars, putting in this way the solar system into context. The survey allows us to address some questions related to the prevalence and properties of planetesimal systems. Methods. We used Herschel/PACS to observe a sample of nearby FGK stars. Data at 100 and 160 μm were obtained, complemented in some cases with observations at 70 μm, and at 250, 350 and 500 μm using SPIRE. The observing strategy was to integrate as deep as possible at 100 μm to detect the stellar photosphere. Results. Debris discs have been detected at a fractional luminosity level down to several times that of the Edgeworth-Kuiper belt. The incidence rate of discs around the DUNES stars is increased from a rate of ∼ 12.1% ± 5% before Herschel to ∼ 20.2% ± 2%. A significant fraction (∼ 52%) of the discs are resolved, which represents an enormous step ahead from the previously known resolved discs. Some stars are associated with faint far-IR excesses attributed to a new class of cold discs. Although it cannot be excluded that these excesses are produced by coincidental alignment of background galaxies, statistical arguments suggest that at least some of them are true debris discs. Some discs display peculiar SEDs with spectral indexes in the 70–160 μm range steeper than the Rayleigh-Jeans one. An analysis of the debris disc parameters suggests that a decrease might exist of the mean black body radius from the F-type to the K-type stars. In addition, a weak trend is suggested for a correlation of disc sizes and an anticorrelation of disc temperatures with the stellar age. [less ▲]

Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant planets are thought to form ... [more ▼]

Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant planets are thought to form according to the core accretion theory of planet formation. In this paper, we report the discovery of a giant planet detected from the analysis of the light curve of a high-magnification microlensing event MOA 2010-BLG-477. The measured planet-star mass ratio is q = (2.181 ± 0.004) × 10[SUP]-3[/SUP] and the projected separation is s = 1.1228 ± 0.0006 in units of the Einstein radius. The angular Einstein radius is unusually large θ[SUB]E[/SUB] = 1.38 ± 0.11 mas. Combining this measurement with constraints on the "microlens parallax" and the lens flux, we can only limit the host mass to the range 0.13 < M/M [SUB]&sun;[/SUB] < 1.0. In this particular case, the strong degeneracy between microlensing parallax and planet orbital motion prevents us from measuring more accurate host and planet masses. However, we find that adding Bayesian priors from two effects (Galactic model and Keplerian orbit) each independently favors the upper end of this mass range, yielding star and planet masses of M [SUB]*[/SUB] = 0.67[SUP]+0.33[/SUP] [SUB]- 0.13[/SUB] M [SUB]&sun;[/SUB] and m[SUB]p[/SUB] = 1.5[SUP]+0.8[/SUP] [SUB]- 0.3[/SUB] M [SUB]JUP[/SUB] at a distance of D = 2.3 ± 0.6 kpc, and with a semi-major axis of a = 2[SUP]+3[/SUP] [SUB]- 1[/SUB] AU. Finally, we show that the lens mass can be determined from future high-resolution near-IR adaptive optics observations independently from two effects, photometric and astrometric. [less ▲]

We present the first far-IR observations of the solar-type stars δ Pav, HR 8501, 51 Peg and ζ2 Ret, taken within the context of the DUNES Herschel open time key programme (OTKP). This project uses the ... [more ▼]

We present the first far-IR observations of the solar-type stars δ Pav, HR 8501, 51 Peg and ζ2 Ret, taken within the context of the DUNES Herschel open time key programme (OTKP). This project uses the PACS and SPIRE instruments with the objective of studying infrared excesses due to exo-Kuiper belts around nearby solar-type stars. The observed 100 μm fluxes from δ Pav, HR 8501, and 51 Peg agree with the predicted photospheric fluxes, excluding debris disks brighter than Ldust/ ~ 5 × 10-7 (1σ level) around those stars. A flattened, disk-like structure with a semi-major axis of ~100 AU in size is detected around ζ2 Ret. The resolved structure suggests the presence of an eccentric dust ring, which we interpret as an exo-Kuiper belt with Ldust/ ≈ 10-5. [less ▲]

GeoArabia Special Publication 1 <br /> <br />Knowledge of the Palaeozoic biostratigraphy of the Arabian Peninsula, situated close to the northern margin of Gondwana, was poorly known until a joint special ... [more ▼]

GeoArabia Special Publication 1 <br /> <br />Knowledge of the Palaeozoic biostratigraphy of the Arabian Peninsula, situated close to the northern margin of Gondwana, was poorly known until a joint special project was held by the Saudi Arabian Oil Company (Saudi Aramco) and the Commission Internationale de Microflore du Paléozoïque (CIMP) in 1990. Prior to that only a small number of investigations had been published. Few efforts had been made to exploit the strati-graphic potentials of the many undescribed indigenous microfossils. The joint Saudi Aramco-CIMP project was designed to reverse that situation. Comprehensive studies were carried out on a range of microfossil groups throughout the Palaeozoic and results were published in 1995. <br /> <br />The 13 papers presented in this GeoArabia Special Publication update those initial findings. They clearly indicate the potential for these palynomorph assemblages to not only to provide a method for well-to-well correlations within Saudi Arabia, but also for establishing the palaeo-biogeographical relationships of the Arabian Plate relative to adjacent landmasses. The conclusions that are proposed here can now be compared with datasets throughout North Africa and with the central and southern parts of South America. <br /> <br />Editors: Sa’id Al-Hajri and Bernard Owens <br />231 pages <br />40 plates/62 illustrations [less ▲]